Articulation Mechanism for Surgical Instrument

ABSTRACT

An articulating elongate surgical instrument includes a handle assembly, an elongated body portion, a tool assembly pivotally supported on the distal end of the elongated body portion. The elongate surgical instrument includes as well an articulation mechanism to effect the movement of the tool assembly, the articulation mechanism including a pivot member operatively coupled to the tool assembly. The elongated body includes at least one articulation drive member having at least one retaining surface therein; a firing rod disposed adjacent the articulation drive, with an articulation locking actuating surface disposed upon the firing rod; and an articulation locking means configured to selectively engage and disengage from the actuating surface and to selectively engage and disengage from the retaining surface of the articulation drive member.

BACKGROUND

1. Technical Field

This application relates to a mechanism to effect movement of at least aportion of a surgical instrument, and more particularly, to anarticulating mechanism for use with an elongate surgical instrument.

2. Background of Related Art

Surgical devices wherein tissue is first grasped or clamped betweenopposing jaw structure and then joined by surgical fasteners are wellknown in the art. In some instruments a knife is provided to cut thetissue which has been joined by the fasteners. The fasteners aretypically in the form of surgical staples but two part polymericfasteners can also be utilized.

A stapler disclosed in U.S. Pat. No. 3,499,591 applies a double row ofstaples on each side of the incision. This is accomplished by providinga disposable loading unit in which a cam member moves through anelongate guide path between two sets of staggered staple carryinggrooves. Staple drive members are located within the grooves and arepositioned in such a manner so as to be contacted by the longitudinallymoving cam member to effect ejection of the staples from the staplecartridge of the disposable loading unit. Other examples of suchstaplers are disclosed in U.S. Pat. Nos. 4,429,695 and 5,065,929.

Each of the instruments described above were designed for use inconventional surgical procedures wherein surgeons have direct manualaccess to the operative site. However, in endoscopic or laparoscopicprocedures, surgery is performed through a small incision or through anarrow cannula inserted through small entrance wounds in the skin. Inorder to address the specific needs of endoscopic and/or laparoscopicsurgical procedures, endoscopic surgical stapling devices have beendeveloped and are disclosed in, for example, U.S. Pat. No. 5,040,715(Green, et al.); U.S. Pat. No. 5,307,976 (Olson, et al.); U.S. Pat. No.5,312,023 (Green, et al.); U.S. Pat. No. 5,318,221 (Green, et al.); U.S.Pat. No. 5,326,013 (Green, et al.); and U.S. Pat. No. 5,332,142(Robinson, et al.).

Certain current laparoscopic linear staplers are configured to operatein an articulated off axis configuration. Samples of articulatingendoscopic surgical staplers are disclosed in U.S. Pat. No. 6,953,139issued to Milliman et al.

SUMMARY

The present disclosure relates to an articulating elongate surgicalinstrument that includes a handle assembly, and an elongated bodyportion extending distally from the handle assembly and defining a firstlongitudinal axis. The elongate surgical instrument also includes a toolassembly pivotally supported on the distal end of the elongated bodyportion about a pivot axis substantially orthogonal to the firstlongitudinal axis. The elongate surgical instrument includes as well anarticulation mechanism to effect the movement of the tool assembly.

The instrument has at least one articulation drive member with at leastone retaining surface; a rod disposed adjacent the at least onearticulation drive member, with an actuating surface disposed upon therod; and an articulation locking assembly configured to selectivelyengage and disengage the actuating surface and to selectively engage anddisengage from the at least one retaining surface of the at least onearticulation drive member.

The at least one articulation drive member can include two articulationdrive members, each of the two articulation drive members having atleast one retaining surface for engagement and disengagement by thearticulation locking assembly. The articulation locking assembly canhave at least two retaining surfaces, at least one of the retainingsurfaces engaging one of the two articulation drive members, and atleast the other of the retaining surfaces engaging the other of the twoarticulation drive members.

The retaining surface or surfaces of the articulation locking assemblymay be configured as one or more protrusions. The protrusions mayselectively engage and disengage from the respective at least oneretaining surface of the articulation drive member. The at least oneretaining surface of the articulation drive members may be configured aschannels receiving the respective protrusions of the articulationlocking assembly.

The at least one retaining surface of the articulation locking assemblymay each include a frictional surface. The at least one retainingsurface of the articulation drive member or members may include africtional surface.

In one embodiment, the articulation locking assembly may include aflexible member that is expansible laterally. The articulation lockingassembly may further include a motive member movable toward the flexiblemember. The actuating surface disposed upon the rod may be configured asa detent channel in a surface of the rod. The detent channel may includeat least one ramp surface configured to urge movement of the motivemember upon motion of the rod.

In one embodiment, the flexible member may have an interior space andwherein, upon motion of the rod, the motive member enters the interiorspace of the flexible member and expands the flexible member laterally.The motive member may have an inclined surface for engaging the flexiblemember.

The flexible member may be configured with sufficient resiliency to urgethe motive member away from the flexible member and to release therebythe drive members to allow movement of the drive members. The flexiblemember may include at least a pair of inclined surfaces spanning theinterior space, and the motive member may be configured wherein motionof the motive member to engage the inclined surfaces of the flexiblemember causes the retaining surfaces of the flexible member to engagewith, or disengage from, the retaining surface of the respectivearticulation drive members. The flexible member may further include anaperture, and the motive member may further include a protrusionconfigured to lockingly engage with and to be received by the apertureof the flexible member. The protrusion of the motive member maylockingly engage with and be received by the aperture of the flexiblemember during motion of the motive member to engage the inclinedsurfaces of the flexible member to cause the retaining surfaces of thearticulation locking means to selectively engage and disengage from theretaining surface of the respective articulation drive members.

In one embodiment, the elongated body portion includes at least twodrive members each having at least two retaining surfaces, an operatinglever, and a base plate. The base plate may be operatively coupled tothe operating lever, with the base plate having first and second pairseach of a distal engaging portion and a proximal engaging portion. Thefirst pair of distal engaging portions may be configured to alternatelyengage the distal engaging apertures upon movement of the operatinglever, while the second pair of proximal engaging portions may beconfigured to alternately engage the proximal engaging apertures uponmovement of the operating lever.

The base plate may further include a plurality of notches, wherein eachof the plurality of notches corresponds to a particular position of thebase plate effecting a particular position of articulation of the pivotmember, and the surgical instrument further includes a locking actuatorlockingly engaging with any one of the plurality of notches in the baseplate to lock a particular position of articulation of the pivot member.

The rod of the instrument may comprise a firing rod for effecting thefiring of surgical staples from the tool assembly.

In a further aspect of the present disclosure, a method of preventingarticulation in a surgical instrument includes moving a rod having anactuating surface thereon, so that the actuating surface engages anarticulation locking assembly. the articulation locking assembly has aflexible member that is cammed laterally to engage at least onearticulation drive member. The method can include that the motive memberis engaged with the rod, the actuating surface urging movement of themotive member. The motive member may be moved toward the flexiblemember. In certain embodiments, the motive member moves into an interiorspace of the flexible member, expanding the flexible member laterally.The method can include moving the motive member into a channel in therod and away from the flexible member. Retaining surfaces on theflexible member can be moved into engagement with retaining surfaces onthe at least one articulation drive member.

In certain embodiments, the flexible member is cammed laterally in twodirections to engage two articulation drive members. The motive membercan slide along at least one inclined surface. In a preferredembodiment, surgical staples are fired from the surgical instrument,including moving the rod in a distal direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are described herein with reference to the drawings:

FIG. 1 is a perspective view of an embodiment of the presently disclosedsurgical stapling apparatus;

FIG. 2 is a perspective view of the articulation mechanism of thesurgical apparatus shown in FIG. 1;

FIG. 3 is a detail of FIG. 2 showing a pivot member and articulationdrive members according to the present disclosure;

FIG. 4 is a detail of FIG. 2 showing the drive members and otherfeatures according to the present disclosure; and

FIG. 5 is a plan view of the proximal end of the articulation mechanismaccording to the present disclosure illustrating the drive members.

FIG. 6 is a perspective view of an articulation operating mechanism andan elongated body portion for an elongate surgical instrument that bothenclose an articulation locking mechanism according to the presentdisclosure;

FIG. 7 is a perspective view with parts separated of the internalcomponents of the elongated body portion of the elongate surgicalinstrument of FIG. 6;

FIG. 8A is a perspective view showing one embodiment of a pivot memberand articulation drive members of the elongated body portion for anelongate surgical instrument of FIG. 6;

FIG. 8B is a side view of the pivot member and an articulation drivemember of the elongated body portion of FIG. 8A;

FIG. 8C is a side view of the pivot member and another articulationdrive member of the elongated body portion of FIG. 8A;

FIG. 9A is a perspective view showing another embodiment of a pivotmember and articulation drive members of the elongated body portion foran elongate surgical instrument of FIG. 6;

FIG. 9B is a side view of the pivot member and articulation drivemembers of the elongated body portion of FIG. 9A;

FIG. 10 is a perspective view with parts separated of internalcomponents of the elongated body portion of the elongate surgicalinstrument of FIG. 8 illustrating one embodiment of an articulationlocking mechanism according to the present disclosure;

FIG. 11 is a perspective view of the articulation locking mechanism ofFIG. 10;

FIG. 12 is a sectional perspective view of the internal components ofthe elongated body portion of FIGS. 6, 7 and 10;

FIG. 13 is another sectional view of the internal components of theelongated body portion, taken along line 13-13 in FIG. 12, showing thearticulation locking mechanism in a disengaged position;

FIG. 14 is a cross-sectional view of the internal components of theelongated body portion of FIGS. 10, 11 and 13 showing the articulationlocking mechanism in a disengaged position;

FIG. 15 is a sectional view of the internal components of the elongatedbody portion of FIGS. 10, 11, 13 and 14 showing the articulation lockingmechanism in an engaged position;

FIG. 16 is a cross-sectional view of the internal components of theelongated body portion of FIGS. 10, 11, 13, 14 and 15 showing thearticulation locking mechanism in an engaged position;

FIG. 17 is a plan view of the internal components of the elongated bodyportion of FIGS. 10, 11, 13, 14, 15 and 16 showing the articulationlocking mechanism in an engaged position;

FIG. 18 is a perspective view of the internal components of theelongated body portion, showing an alternate configuration ofarticulation drive member retaining surfaces;

FIG. 19 is a perspective view of the internal components of theelongated body portion, showing an alternate configuration ofarticulation drive member retaining surfaces;

FIG. 20 is a cross-sectional view of the internal components of theelongated body portion of FIG. 19 showing the articulation drive memberretaining surfaces in an engaged position; and

FIG. 21 is a plan view of the internal components of the elongated bodyportion of FIGS. 19 and 20 showing an alternate configuration ofarticulation drive member retaining surfaces in an engaged position.

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described in detailwith reference to the drawings, in which like reference numeralsdesignate identical or corresponding elements in each of the severalviews.

In the drawings and in the description that follows, the term“proximal”, as is traditional, will refer to the end or portion of thesurgical instrument which is closest to the operator, while the termdistal will refer to the end or portion of the surgical instrument whichis furthest from the operator.

Referring now to FIGS. 1-5, an elongate surgical instrument, e.g. asurgical stapling apparatus for applying surgical staples, according tothe present disclosure is shown generally as surgical instrument 10.Surgical instrument 10 generally includes a handle assembly 12 having ahousing 16 with a handle portion 18 and a movable trigger portion 20.The surgical instrument 10 includes an elongated body 14 operativelycoupled to the housing 16. An articulation lever 130 is also mounted onthe forward end of handle assembly 12 to facilitate articulation of toolassembly 17. In one embodiment, tool assembly 17 is releasably securedto a distal end 19 of elongated body 14. As illustrated in FIGS. 1-2,the tool assembly 17 has a pair of jaws 23 a and 23 b including an anvilassembly 23 a and a cartridge assembly 23 b. The anvil assembly 23 a ismovably secured in relation to elongated body 14. The anvil assembly 23a is disposed in opposition to the cartridge assembly 23 b and thecartridge assembly 23 b is configured to apply linear rows of staples.Replaceable loading units with tool assemblies for applying rows ofstaples measuring from about 30 mm to about 60 mm in length may beconnected to the distal end 19 of elongated body 140. Replaceableloading units having linear rows of staples of other lengths are alsoenvisioned, e.g., 45 mm. The deployment of the surgical staples and theactuation mechanism therefor is disclosed in U.S. Patent ApplicationPublication No. 2004/0232201 A1, the entire disclosure of which ishereby incorporated by reference herein.

The general overall arrangement, construction and operation of surgicalinstrument 10 embodied as an endoscopic surgical stapling apparatus issimilar in many respects to a surgical stapling apparatus such as, forexample but not limited to, that described in more detail in commonlyassigned U.S. Pat. No. 6,953,139 B2, by Milliman et al, published Oct.11, 2005, the entire contents of which is hereby incorporated byreference herein. The surgical instrument 10 may also be embodied as agrasping instrument, a retractor or as another instrument requiringarticulation of a surgical tool member. The embodiments are not limitedto the context of an endoscopic surgical stapler.

In an embodiment according to the present disclosure, the surgicalinstrument 10 further includes an articulation mechanism 100 (see FIG.2) to effect the movement of the tool assembly 17. The articulationmechanism 100 includes a pivot member 102 that is operatively coupled tothe tool assembly 17 at a proximal end 21 thereof (see FIG. 1). Theelongated body portion 14 extends distally from the handle assembly 12and defines a first longitudinal axis. The tool assembly 17 is pivotallysupported by the pivot member 102 on the distal end of the elongatedbody portion 14 about a pivot axis defined by the pivot member 102 thatis substantially orthogonal to the first longitudinal axis. The toolassembly 17 defines a second longitudinal axis and is movable between afirst position in which the second longitudinal axis is aligned with thefirst longitudinal axis to a second position in which the secondlongitudinal axis is positioned at an angle to the first longitudinalaxis.

The articulation mechanism 100 is further configured with at least firstand second articulation drive members 110 a and 110 b, respectively,that are operatively coupled to the pivot member 102 such that relativemotion of the first articulation drive member 110 a with respect to thesecond articulation drive member 110 b moves the pivot member 102 toeffect the movement of the tool assembly 17.

The articulation mechanism 100 may further include an actuation assembly104. The actuation assembly 104 includes at least first and secondarticulation drive plates 112 a and 112 b, respectively. The firstarticulation drive plate 112 a may be operatively coupled to at leastthe first articulation drive member 110 a, while at least the secondarticulation drive plate 112 b may be operatively coupled to at leastthe second articulation drive member 110 b, such that relative motion ofone of the first and second articulation drive plates 112 a or 112 b,respectively, with respect to another one of the first and secondarticulation drive plates 112 b or 112 a, respectively, moves the pivotmember 102 to effect the movement of the tool assembly 17. In oneembodiment, the drive members 110 a and 110 b may be formed of strips orbars that are flat or rounded. In one embodiment, the first and secondarticulation drive members 110 a and 110 b, respectively, are configuredto be disposed within the elongated body portion 14.

The drive plates 112 a and 112 b may be coupled orthogonally to therespective drive members 110 a and 110 b. The drive plates 112 a and 112b may be configured as rectangular plates each having at least a distalengaging aperture 114 a, 114 b or a proximal engaging aperture 116 a,116 b, respectively, formed therein. Each aperture 114 a, 114 b, and 116a, 116 b defines an inner surface 118 a, 118 b and 120 a, 120 b,respectively.

The articulation mechanism 100 may further include an articulation drivebar 130 that is configured to contact the drive plates 112 a and 112 b,such that upon contacting the drive plates 112 a and 112 b, movement ofthe articulation drive bar 130 effects movement of the drive plates 112a and 112 b to effect the movement of the tool assembly 17.

In one embodiment, the articulation drive bar 130 is configured toengage at least the distal or proximal engaging apertures 114 a, 114 bor 116 a, 116 b, respectively, of each of the first and second driveplates 112 a and 112 b, respectively, such that upon engaging at leastthe distal or proximal engaging apertures 114 a, 114 b and 116 a, 116 b,thereby, movement of the articulation drive bar 130 effects movement ofthe tool assembly 17.

The articulation drive bar 130 is configured to contact the innersurfaces 118 a, 118 b, 120 a, 120 b of at least the distal or proximalengaging apertures 114 a, 114 b or 116 a, 116 b, respectively, of eachof the drive plates 112 a, 112 b such that upon contacting the innersurfaces 118 a, 118 b, 120 a, 120 b thereby, movement of thearticulation drive bar 130 effects movement of the tool assembly 17.

The articulation drive bar 130 may include an operating lever 140 and abase plate 150 that is operatively coupled to the operating lever 140.In one embodiment, as illustrated in FIGS. 2, 4 and 5, the base plate150 has a bow-tie configuration with four protrusions around theperiphery thereof such as first and second pairs each of distal engagingportions 152 a and 152 b and proximal engaging portions 154 a and 154 b,respectively. The distal engaging portions 152 a and 152 b areconfigured to engage the distal engaging apertures 114 a and 114 b,respectively, upon movement of the operating lever 140, while theproximal engaging portions 154 a and 154 b are configured to alternatelyengage the proximal engaging apertures 116 a and 116 b, respectively,upon movement of the operating lever 140.

Referring to FIG. 5, the base plate 150 may further include a pluralityof notches 156 disposed at the proximal portion of the periphery of thebase plate 150. Each of the plurality of notches 156 corresponds to aparticular position of the base plate 150 as it is rotated around avertical centerline axis Y-Y to effect a particular position ofarticulation of the pivot member 102. Axis Y-Y is shown in FIG. 4, alocking actuator, e.g., locking pin 160, engages with one of theplurality of notches 156 in the base plate 150 to define a predeterminedarticulated position of the tool assembly 17.

The surgical apparatus 10 may further include a tensioner, e.g., coilsprings 170 a and 170 b, operatively coupled to the surgical apparatus10, e.g., at the proximal ends 122 a and 122 b of the first and secondarticulation drive plates 112 a and 112 b, respectively, such that thetensioner provides tension to the relative movement of the articulationdrive members 110 a and 110 b.

The articulation drive members 110 a, 110 b, the articulation driveplates 112 a, 112 b and the articulation drive bar 130 of thearticulation mechanism 100 and associated components may be made frommaterials such as plastic, metal or metal alloy, or other suitablematerial.

In operation, the user engages the operating lever 140, turning it tothe left or right. When the user turns the operating lever 140 to theright, from the perspective of the user, as shown in FIGS. 1 and 5,proximal engaging portion 154 b advances second articulation drive plate112 b in a distal direction. The base plate 150 may also be arranged sothat distal engaging portion 152 a retracts first articulation driveplate 112 a in a proximal direction, as drive plate 112 b is advanced.Pivot member 102 pivots so that the tool assembly 17 articulates to theleft, as shown in FIG. 1.

As can be appreciated from the above description, the present disclosureprovides an articulating endoscopic surgical instrument 10 that includeselongate body portion 14. The elongate body portion 14 defines firstlongitudinal axis A-A (see FIG. 1). The endoscopic surgical instrument10 also includes articulating tool assembly 17 that has the pair of jaws23 a and 23 b (shown in FIG. 1 in the closed position). The articulatingtool assembly 17 defines a second longitudinal axis B-B (see FIG. 1).The articulating tool assembly 17 is disposed at a distal end 19 of thebody portion 14 and is movable from a first position in which the secondlongitudinal axis B-B is substantially aligned with the firstlongitudinal axis A-A to at least a second position in which the secondlongitudinal axis B-B is disposed at an angle θ to the firstlongitudinal axis A-A. The articulating endoscopic instrument 10 alsoincludes the articulation mechanism 100 and the tool assembly 17 that isoperatively coupled to the pivot member 102 to effect articulation ofthe tool assembly 17.

The pivot member 102 is pivotably attached to the elongate body portion14 at the pivot axis Y-Y (see FIG. 4). The first articulation drivemember 110 a and the second articulation drive member 110 b are attachedto the pivot member 102 so that relative movement of the articulationdrive members 110 a, 110 b articulates the tool assembly 17. The firstarticulation drive member 110 a is attached to the pivot member 102 on afirst side of the pivot axis X-X and the second articulation drivemember 110 b is attached to the pivot member 102 on a second side of thepivot axis X-X.

The actuation assembly 104, including the rotatably mounted base 150, isoperatively associated with the first and second articulation drivemembers 110 a and 110 b, respectively, so that upon rotation of theoperating lever 140, the first articulation drive member 110 a moves ina proximal direction and the second articulation drive member 110 bmoves in a distal direction.

Referring now to FIGS. 6-21, there is disclosed an embodiment of anarticulation locking mechanism for an articulating elongate surgicalinstrument. In FIGS. 6-21, only those portions of the articulatingsurgical instrument are illustrated as necessary to describe thearticulation locking mechanism construction and operation. Moreparticularly, referring to FIG. 6, an articulation operating assembly230 for an elongate surgical instrument includes a pair of upper andlower sections 232 and 234 housing an elongated body portion 214operatively coupled to the housing (not shown) of the elongate surgicalinstrument (not shown).

FIG. 7 is a perspective view with parts separated of the internalcomponents of the elongated body portion 214. The elongated body portion214 includes at least one articulation drive member having at least oneretaining surface therein, e.g., first and second articulation drivemembers 210 a and 210 b, respectively, each having a retaining surface205 a and 205 b, respectively, therein. A firing rod 216 may be disposedadjacent to the articulation drive member or members, e.g., the firingrod 216 may be disposed adjacent to the first articulation drive member210 a and adjacent to the second articulation drive member 210 b. Anactuating surface 250, may be disposed upon the firing rod 216.

The elongated body 214 also includes an articulation locking means orarticulation locking assembly 260 that is configured to selectivelyengage and disengage from the actuating surface 250 and to selectivelyengage and disengage from the at least one retaining surface of the atleast one articulation drive member, e.g., retaining surface 205 a and205 b selectively engaging and disengaging from the articulation drivemembers 210 a and 210 b, respectively.

The articulation locking means 260 may be configured to selectivelyengage and disengage from the actuation surface 250 and with the atleast one retaining surface of the articulation drive members, e.g.,with the retaining surfaces 205 a and 205 b of the articulation drivemembers 210 a and 210 b, respectively. The articulation locking means260 includes two retaining surfaces 265 a and 265 b that selectivelyengage and disengage from the retaining surfaces 205 a and 205 b of therespective articulation drive members 210 a and 210 b.

The retaining surfaces, e.g., retaining surfaces 265 a and 265 b, of thearticulation locking means 260 may be configured as protrusions, whereineach of the protrusions 265 a and 265 b selectively engages anddisengages from the respective retaining surfaces 205 a and 205 b, ofthe articulation drive members 210 a and 210 b, respectively.

In one embodiment, retaining surfaces 205 a and 205 b of thearticulation drive members 210 a and 210 b, respectively, include atleast two retaining surfaces, e.g., retaining surfaces 215 a 1, 215 a 2,215 a 3, 215 a 4, 215 a 5 and 215 b 1, 215 b 2, 215 b 3, 215 b 4, 215 b5, respectively. The retaining surfaces, e.g., retaining surfaces 215 a1, 215 a 2, 215 a 3, 215 a 4, 215 a 5 and 215 b 1, 215 b 2, 215 b 3, 215b 4, 215 b 5, respectively, may each be configured as channels receivingthe respective protrusions 265 a and 265 b of the articulation lockingmeans 260. The retaining surfaces 215 a 1, 215 a 2, 215 a 3, 215 a 4,215 a 5 may be disposed on at least one of an upper edge 210 a′ and alower edge 210 a″ of the articulation drive member 210 a while theretaining surfaces 215 b 1, 215 b 2, 215 b 3, 215 b 4, 215 b 5 may bedisposed on at least one of an upper edge 210 b′ and a lower edge 210 b″of the articulation drive member 210 b. The articulation drive memberchannels 215 a 1, 215 a 2, 215 a 3, 215 a 4, 215 a 5 and 215 b 1, 215 b2, 215 b 3, 215 b 4, 215 b 5 may be configured as at least one of openchannels, as illustrated in FIG. 7, and as closed channels 215 a 1′, 215a 2′, 215 a 3′, 215 a 4′, 215 a 5′ and 215 b 1′, 215 b 2′, 215 b 3′, 215b 4′, 215 b 5′, as illustrated in FIG. 18, or may have other shapes. Incertain embodiments, retaining surfaces are provided only on one of theupper or lower edges of the articulation drive members. In otherembodiments, retaining surfaces are provided on both edges, to providesymmetry for manufacturing purposes, or for engagement by a secondlocking means.

FIG. 7 also illustrates that the drive members 210 a and 210 b eachinclude a proximal end 212 a and 212 b, respectively, and a distal end212 a′ and 212 b′, respectively. At the distal ends 212 a′ and 212 b′,there is disposed a pivot engaging joint 218 a and 218 b, respectively,that is illustrated in FIGS. 7, 8A and 8B as being exemplified by aU-shaped loop joint.

At distal end 212 a′, the elongated body member 214 includes a pivotmember 202 that is operatively coupled to an anvil assembly, such asanvil assembly 23 a (see FIG. 1) and cartridge assembly 23 b (see FIGS.1-3 and 8A). The anvil assembly 23 a is movably secured in relation toelongated body 214.

The pivot engaging joints 218 a and 218 b are disposed within the pivotmember 202 to connect the drive members 210 a and 210 b to the pivotmember 202. A pivot engaging joint 218 a′ is configured in an invertedU-shaped loop so as to engage with the vertical U-shaped loop of pivotengaging joint 218 a via a sleeve 220, while a pivot engaging joint 218b′ is configured in a vertical U-shaped loop so as to engage with theinverted U-shaped loop of pivot engaging joint 218 b via another sleeve220 (see FIGS. 8B and 8C).

FIGS. 9A and 9B illustrate an alternate configuration of the pivotmember 202 and of the distal ends 212 a′ and 212 b′ of drive members 210a and 210 b. More particularly, distal ends 212 a″ and 212 b″of drivemembers 210 a and 210 b pivot member 202′ are each configured with pivotengaging joints 228 a and 228 b, respectively, having a T-shapedconfiguration having arms 228′ of the T-shape. A pivot member 202′ isconfigured with sleeves 222 that are disposed in the pivot member 202′to receive the arms 228′ of the T-shaped distal ends 212 a″ and 212 b″,respectively.

Referring to FIGS. 19-21, in one embodiment, the retaining surfaces ofthe articulation locking means, e.g., retaining surfaces 265 a and 265 bof the articulation locking means 260, may each include a frictionalsurface. Frictional surfaces 265 a′ and 265 b′, respectively,selectively engage and disengage from the retaining surfaces 205 a and205 b of the articulation drive members 210 a and 210 b, respectively.The frictional surfaces 265 a′ and 265 b′ selectively engage anddisengage with respective frictional surfaces 225 a and 225 b. Thefrictional surfaces 265 a′, 265 b′ and 225 a, 225 b are formed from amaterial or are textured to increase friction between the drive membersand the locking means 260 and resist movement of the drive members 210 aand 210 b.

As best shown in FIGS. 10-17, the articulation locking means 260 isconfigured to selectively engage and disengage from the actuatingsurface 250 and selectively engage and disengage from retaining surfaces205 a and 205 b of articulation drive members 210 a and 210 b,respectively.

The articulation locking means 260 may include a motive member, e.g., aplunger 264, that is configured to selectively engage and disengage froma flexible member 262, or interact with the flexible member 262, toeffect engagement and disengagement of the retaining surfaces 265 a and265 b from the retaining surfaces 205 a and 205 b of drive members 210 aand 210 b, respectively.

The actuating or actuation surface 250 and the motive member 264 may beconfigured wherein motion of a component within the elongate body 214effects motion of the motive member 264. The actuating surface 250 offiring rod 216 may be configured as a detent channel 252 in a surface216′ of the firing rod 216. The detent channel 252 includes at least oneramp surface 252 a configured to urge movement of the motive member 264upon motion of the firing rod 216.

The flexible member 262 may be configured in a loop-type arrangementhaving an interior space 266. Upon motion of the firing rod 216, themotive member 264 enters the interior space 266 and is urged towards theflexible member 262 and interacts with the flexible member 262 so as tomove protrusions 265 a and 265 b towards the drive members 210 a and 210b.

The flexible member 262 includes inclined surfaces 266 a and 266 bspanning the interior space 266. The firing rod 216 is moved forward, sothat motive member 264 rides up out of channel 252. When motive member264 rests on surface 216′ (see FIG. 10), the flexible member 262 isengaged with the drive members 210 a and 210 b. The motive member 264 isarranged and configured to laterally expand the sides of the flexiblemember 262. The motive member 264 has inclined surfaces 269 a, 269 bthat engage the inclined surfaces 266 a and 266 b of the flexible member262 so that as the motive member 264 is urged towards the flexiblemember 262, the sides of flexible member 262 (which carry protrusions265 a and 265 b) are cammed laterally towards the drive members 210 aand 210 b. The protrusions 265 a and 265 b engage retaining surfaces 205a and 205 b. Guidance rib 270 on the motive member 264 preventslongitudinal movement of the motive member 264, through engagement withslot 267 in the flexible member 262.

The flexible member 262 is preferably configured to have sufficientresiliency to urge the motive member 264 away from the flexible member262, thereby releasing the drive members 210 a and 210 b and allowingmovement thereof When the firing rod 216 is retracted, the motive member264 will align with the channel 252, allowing the motive member 264 tomove away from the flexible member 262. The resilient nature of theflexible member 262 moves the sides of the flexible member 262 inwardly,moving the retaining surfaces 265 a, 265 b away from retaining surfaces205 a, 205 b. The firing rod 216 can be a rod for actuating the firingof the staples or a rod dedicated to locking the position of the toolassembly 17. In certain alternative embodiments, the firing rod 216 hasan actuating feature 250 that is formed as a protrusion on the firingrod 216. When the firing rod 216 is moved, the motive member 264 ridesup on a ramp surface of the protrusion, engaging the flexible member262.

As can be appreciated, the embodiments of the articulation mechanism 100and the articulation locking means 260 and the associated componentswithin the elongated body 214, described above, may be applied tosurgical instruments other than a stapling apparatus. Examples includegrasping instruments or retractors.

In further embodiments, one articulation drive member 210 is providedand the articulation locking means has retaining surfaces on one side,arranged to engage retaining surfaces on the articulation drive member.

In certain embodiments, the tool assembly 17 is provided as a removableand replaceable assembly attached to the elongate body portion 14. Thetool assembly 17 and a housing portion that attaches to the elongatebody portion 14 form a loading unit that includes one or more links thatconnect with the one or more drive members of the articulation assembly.

Although the subject disclosure has been described with respect toexemplary embodiments, it will be readily apparent to those havingordinary skill in the art to which it appertains that changes andmodifications may be made thereto without departing from the spirit orscope of the subject disclosure as defined by the appended claims.

1-16. (canceled)
 17. A method of preventing articulation in a surgicalinstrument, comprising moving a rod having an actuating surface thereon,so that the actuating surface engages an articulation locking assembly,the articulation locking assembly having a flexible member that iscammed laterally to engage at least one articulation drive member. 18.The method of claim 17, further comprising engaging a motive member withthe rod, the actuating surface urging movement of the motive member. 19.The method of claim 18, wherein the motive member is moved toward theflexible member.
 20. The method of claim 19, wherein the motive membermoves into an interior space of the flexible member, expanding theflexible member laterally.
 21. The method of claim 19, furthercomprising moving the motive member into a channel in the rod and awayfrom the flexible member.
 22. The method of claim 17, further comprisingmoving retaining surfaces on the flexible member into engagement withretaining surfaces on the at least one articulation drive member. 23.The method of claim 17, further comprising camming the flexible memberlaterally in two directions to engage two articulation drive members.24. The method of claim 19, further comprising sliding the motive memberalong at least one inclined surface.
 25. The method of claim 17, furthercomprising firing surgical staples from the surgical instrument,including moving the rod in a distal direction.